The invention relates to a transporting and lifting vehicle for heavy loads, in particular for converter exchange vessels used in steel production. The vehicle has a travelling frame and a lifting frame that carries a lifting means and receives the converter. The travelling frame is preferably rotatable about a vertical axis for the purpose of transposition at track intersections.
Transporting and lifting vehicles that travel on rails are used for lowering converter exchange vessels, which have to be relined from time to time, from the converter stand, transporting them to a distant lining and repair stand and lifting them into the repair stand. The removed converter is replaced by a spare vessel, which is lifted into the converter stand by means of the transporting and lifting vehicle so that the steel production may be continued. Since a direct rail connection between converter stand and lining stand is often not possible, a transporting and lifting vehicle must be capable of changing its travelling direction to rail intersections at any angle without additional devices, such as turntables or other auxiliary devices which do not form part of the vehicle. When mounting the converter it should also be possible to carry out adjusting movements of the vehicle with the converter vessel in lifted position so that it can be brought into a position corresponding to the bearing zones in the converter carrying ring.
Apart from the carrying capacity the effective lifting height of the lifting mechanism is an essential characteristic of a transporting and lifting vehicle. This lifting height may have to change depending on the construction of the converter plant. Thus, converter construction provided with a horseshoe-shaped carrying ring open at one side require small to medium lifting heights of approx. 0.5 to 1.5 m depending on whether the converter is secured to the upper or lower side of the carrying ring. However, converter constructions provided with a closed carrying ring in general need a comparatively large lifting height of approx. 3 to 4 m, since in this case the lifting height when removing the converter relates to the converter hood.
Moreover, on account of the location of surrounding constructions, such as e.g high platforms, crane runways, etc., it may be necessary to lower the converter below the height that is essential when removing the converter from the carrying ring. It is possible that it may have to be lowered as far as immediately above the mill floor and transported in this position in order to avoid a collision with the surrounding constructions.
Since closed converter carrying rings, as compared to carrying rings open at one side, have the advantage of greater stability and nondeformability it is advantageous to use them, particularly for large and heavy exchange converters, wherein faultless and economical handling of the task of the transporting and lifting vehicle, namely to moving heavy loads over wide lifting ranges, is a prerequisite.
It would be desirable to provide an operationally reliable transporting and lifting vehicle, by means of which the load may be lowered to the rail level and may in turn be lifted to any mounting position, even to a considerably high one.
The known transporting and lifting vehicles do not meet these demands or do not meet them completely. If they did fulfill the above demands their lifting means would become too heavy and uneconomical. Thus, transporting and lifting vehicles, e.g. as they are described in German Auslegeschrift No. 2,023,965, in which vehicles load carrying parts act below the vessel bottom, are not suited for solving this task, since there would be no room for them when the converter is in lowered position.
Yet constructions in which column-like lifting elements are provided for lifting the load, in particular hydraulic piston mechanisms, and whose lifting path is equal to the load path (see e.g. German Auslegeschrift No. 1,433,664) are not well suited for the purpose either, because the required cylinder and piston dimensions with high lifting heights would be disproportionately large on account of the long guiding and buckling lengths, hence, would be uneconomical.
In another known transporting vehicle, as it is described in the German Auslegeschrift No. 1,916,843 the lifting height of the hydraulic piston mechanisms is reduced in that a carrying frame receiving the converter is rotatably supported in a ring, which in turn is suspended on chains or ropes guided over guide pulleys and secured to the vehicle frame. The guide pulleys themselves are carried by piston rods of the hydraulic piston mechanisms that have their cylinder housings firmly connected with the travelling frame. With this arrangement of the lifting mechanism a single force path, yet with double the lifting power of the lifting pistons, a load path which is twice as long as the piston stroke is covered. The disadvantages of this construction lie, however, in the fact that the lifting elements have to be built heavily on account of the load transmission to a faster movement, that additional machine elements which are subject to heavy wear, such as guide pulleys and drawing means, are necessary and that with large lifting heights for the load the lifting elements have to have a considerable length on account of the unalterable transmission of the "loose pulley".